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1.
To completely replace the fish meal by a mixture of earthworm and maggot meals, experimental diets were tested during 42 days on Clarias gariepinus fingerlings. Five isoproteic and isoenergetic diets (40 % crude protein and 17.9 ± 0.3 kJ g?1) including the control diet (D1) based on fish meal, were formulated. All these diets satisfied the essential amino acids requirements of C. gariepinus fingerlings. These diets were tested on triplicate groups of 50 fishes (initial body weight: 3 ± 0.1 g) bred in tank (0.5 m3). The approximate ratios 2:5; 1:4; 1:12 and 0:1 between the earthworm meal and the maggot meal were used, respectively, to formulate four diets D2, D3, D4 and D5 without fish meal. After the feeding period, significant differences (P < 0.05) were observed on growth, feed utilization between control diet (D1) and test diets (D2–D5). Fish fed earthworm- and maggot-based diets were grown better than those fed the control diet. Survival and feed utilization were not significantly affected by the ratio between earthworm meal and maggot meal in the test diets. Lipid content was higher in carcass and fillet of fishes fed earthworm- and maggot meals-based diets than that of those fed fish meal-based diet. This study indicates that when the ratio 2:5 between the earthworm meal and the maggot meal is used to entirely replace fish meal and the ratio lysine/arginine of the diet is inferior to 1, the growth performances and feed utilization of Clarias gariepinus fingerlings are improved.  相似文献   

2.
A feeding experiment was conducted to investigate the effects of exogenous non-starch polysaccharide (NSP)-degrading enzymes in diets containing Gracilaria lemaneiformis (GL) on growth performance and digestive enzyme activities of white-spotted snapper Lutjanus stellatus Akazaki (initial mass 8.0 ± 0.1 g). A basal diet (D0) containing a mixed protein source (fish meal, soybean meal and GL meal) was used as the control. Two diets supplemented with 0.5 g (D1) and 1 g (D2) exogenous NSP-degrading enzymes per kilogram of diet were formulated. Each diet was assigned to triplicate groups of fish in a total of nine floating sea cages (270 fish, 30 fish per cage). After a 60-day feeding trail, significantly higher weight gain, specific growth ratio and feed efficiency ratio were observed in fish fed D2 diet compared to those of control (P < 0.05). Body lipid, moisture and ash contents were not significantly affected by NSP-degrading enzyme supplementation, but significantly higher protein content was noticed in fish fed D2 diet compared to that of control (P < 0.05). The amylase activity in the stomach and intestine was significantly higher in fish fed D2 diet (P < 0.05), but no significant differences were observed in pepsin and lipase activities in the stomach or trypsin and lipase activities in the intestine between all treatments. The results suggested that addition of 1 g kg?1 NSP-degrading enzymes in diet could efficiently improve seaweed feed utilization and growth performance of white-spotted snapper fish.  相似文献   

3.
The effects of replacing fish meal (FM) with corn gluten meal (CGM) on growth and physiological performance were evaluated in common carp (Cyprinus carpio). Six experimental diets were formulated by substituting 0 (control), 20, 40, 60, 80, and 100% CGM protein for FM protein. The concentrations of dietary protein in the experimental diets were 27.8–29% and the P:E ratios were 14.7–15.46 mg/kJ. Eighteen fish with an initial weight of 13.5?±?0.1 g were allocated to each of 18 circular tanks (450 L) to give triplicate groups for each dietary treatment. The fish were fed to satiation for 8 weeks. At the end of the feeding trial, growth indices, body proximate composition, and hematological and biochemical parameters were measured. Blood samples were taken from six fish in each tank. Final weight and total length were significantly higher in fish fed 100% CGM (27.8?±?1.2 g and 11.9?±?0.3 cm) than for those fed the control (22.7?±?1.4 g and 10.9?±?0.5 cm) or 20% CGM (22.3?±?1.2 g and 11?±?0.4 cm) diets. No effect of FM replacement by CGM was observed for condition factor or hepatosomatic index (P?>?0.05). The highest value of protein productive value (14.31?±?0.65) was observed in fish fed 20% CGM (P?<?0.05). There were no significant differences in percentage body moisture and fat, but percentages of protein and ash were significantly different among experimental groups; the highest values of protein (15.6?±?0.24%) and ash (3.01?±?0.26%) were recorded in fish fed 40% CGM. For hematological parameters, the highest number of white blood cells (4.1?±?0.1?×?103 mm?3) was observed in fish fed 100% CGM (P?<?0.05). In addition, the highest hematocrit (42.1?±?0.7%) and triglyceride (294.11?±?23.82 mg dl?1) were seen in fish fed the diet containing 40% CGM, while 80% CGM gave the highest cholesterol level (204.44?±?9.0 mg dl?1; P?<?0.05). Replacement of FM with CGM had no negative effects on growth and physiological parameters of common carp fingerlings in this short (8 weeks) trial, suggesting that it may be feasible to replace FM with CGM in diets formulated for juvenile common carp.  相似文献   

4.
We investigated the effects of replacing non-fermented wheat grains with wheat grains fermented by fungal mycelia in the diet of juvenile rainbow trout (Oncorhynchus mykiss). We assessed growth performance, feeding parameters, and body composition in three experimental groups (0.33?±?0.01 g, in triplicates of 50 individuals each). The diets for all the groups contained ca. 43% protein and 19% lipids. Experimental diets were made by replacing the 100 g kg?1 of wheat grains present in the basal diet (CTRL) with the same proportion of wheat grains fermented by Pleurotus ostreatus (PWD) or Lentinus edodes (LWD) mycelium. Fish were fed to apparent satiation twice a day for 56 days. Both, PWD and LWD, significantly increased fish body weight from day 28 onwards. Final body weight was 2.37?±?0.04 g (CTRL), 4.29?±?0.02 g (PWD), and 3.50?±?0.05 g (LWD), and feeding efficiency (%) was increased from 64.5?±?0.7 (CTRL) to 92.5?±?0.5 (PWD) and 84.8?±?1.5 (LWD). The experimental diets also improved nutrient retention efficiency (%): 30.0?±?0.5 (PWD), 27.7?±?1.1 (LWD), and 21.0?±?0.1 (CTRL), for crude protein; 40.3?±?0.6 (PWD), 31.0?±?1.8 (LWD), and 16.1?±?0.7 (CTRL), for ether extract; and 16.1?±?0.1 (PWD), 14.0?±?0.3 (LWD), and 11.6?±?0.6 (CTRL), for phosphorus. Body lipid content was highest for PWD followed by LWD and CTRL (81.4?±?1.4, 63.2?±?2.5, 42.3?±?2.6 g kg?1, respectively), while viscerosomatic index was lowest for PWD (p?<?0.05). Liver glycogen in LWD and PWD fish (0.62?±?0.10 and 0.21?±?0.08% liver weight) was significantly higher than in CTRL fish (0.05?±?0.01% liver weight). Wheat-mycelium meals appear to be suitable dietary ingredients for improving juvenile rainbow trout growth and nutritional performance. These benefits vary according to the mushroom species used.  相似文献   

5.
As amino acids (AAs) are vital molecules in the metabolism of all living organisms and are the building blocks of enzymes, a 6-week feeding trial was conducted for determining the influence of dietary essential amino acid (EAA) deficiencies on pancreatic, plasma, and hepatic enzyme activities in silvery-black porgy (initial weight 4.7?±?0.01 g) juveniles. Eleven isoproteic (ca. 47%) and isoenergetic (ca. 20.5 MJ kg?1) diets were formulated including a control diet, in which 60% of dietary nitrogen were provided by intact protein (fish meal, gelatin, and wheat meal) and 40% by crystalline AA. The other 10 diets were formulated by 40% reduction in each EAA from the control diet. At the end of the experiment, fish fed with threonine-deficient diet showed the lowest survival rate (P?<?0.05), whereas growth performance decreased in fish fed all EAA-deficient diets, although the reduction in body growth varied depending on the EAA considered. Pancreatic enzymes (trypsin, lipase, α-amylase, and carboxypeptidase A) activities significantly decreased in fish fed the EAA-deficient diets in comparison with fish fed the control diet (P?<?0.05). Fish fed with the arginine-deficient diet had the highest plasma and liver alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels (P?<?0.05). Plasma and liver lactate dehydrogenase and superoxide dismutase showed the highest and lowest values, respectively, in fish fed the arginine and lysine-deficient diets (P?<?0.05). Plasma metabolites were significantly affected by dietary EAA deficiencies (P?<?0.05). The results of this study suggesting dietary EAA deficiencies led to reduction in growth performance as well as pancreatic and liver malfunction. Furthermore, arginine and lysine are the most limited EAA for digestive enzyme activities and liver health in silvery-black porgy.  相似文献   

6.
A 60-day feeding trial was conducted to evaluate the nutritional potential of fermented Jatropha kernel meal (FJKM) in the diets of rohu, Labeo rohita, fingerlings. Four iso-nitrogenous (336 g kg?1) and iso-energetic (20 MJ kg?1) diets containing 0, 100, 200, and 300 g kg?1 FJKM in replacement of 0, 33.3, 66.7, and 100% soybean meal protein, respectively, were prepared and designated as control, T1, T2, and T3, respectively. A total of 180 acclimatized fish (average weight 6.05?±?0.04 g) were equally distributed into four experimental groups in triplicates, and were fed their respective diets to satiation twice daily at 10:00 h and 18:00 h. Higher percent weight gain (%WG); specific growth rate (SGR); protein efficiency ratio (PER); protease, aspartate amino transferase (AST), and alanine amino transferase (ALT) activities; and lower feed conversion ratio (FCR) were recorded in T2 and T3 groups compared to other groups. Whereas hepatosomatic index (HSI), intestinal somatic index (ISI), and amylase, lactate dehydrogenase (LDH), malate dehydrogenase (MDH), superoxide dismutase (SOD), and catalase activities among the various dietary groups did not vary significantly (P?>?0.05). Whole body composition of fish analyzed at the end of the feeding trial exhibited significantly (P?<?0.05) higher ether extract and lower crude protein in the control group compared to the FJKM-fed groups. These results indicated that rohu fingerlings can efficiently utilize FJKM without any detrimental effect on growth performance, nutrient utilization, and metabolic response.  相似文献   

7.
The present study aims to evaluate the effects of several types of larval feed on seed production of the oriental river prawn Macrobrachium nipponense and water quality in extensive rearing systems. Healthy M. nipponense were distributed into fifteen 15-m2 pond outdoors, and each pond was stocked with 90 prawns including 41 egg-bearing (berried) female prawns, 37 not bearing female prawns, and 12 male prawns for larval production. The experimental design was completely randomized, with four diet groups (diet A: soybean homogenate, diet B: yeast, diet C: yeast?+?fermented soybean meal, and diet D: yeast?+?fermented soybean meal?+?microparticulate diet) and one no feeding control and three replications. There are equal levels of the total protein content in diets A–D. Higher larvae and postlarvae number was obtained for diet C and diet D. Furthermore, the increase of M. nipponense larvae and postlarvae in diets B–D can result in the decrease of zooplankton and increase of phytoplankton in the pond during some periods, simultaneously improving the water quality. The Spearman correlation coefficient (rM,N) between the amounts of larvae and postlarvae of M. nipponense per pond and zooplankton per pond during the entire experiment period was ??0.56. The highest juvenile M. nipponense production was obtained in the diet D group (3140.00?±?461.63), which was slightly higher than that in the diet C group (2940.33?±?382.60). The juvenile M. nipponense production in diet B (2303.00?±?449.23) was also significantly higher compared to diet A (1106.33?±?176.64) and the control group (1039.67?±?212.85). There were no significant differences in the amounts of juvenile M. nipponense between the control and diet A groups, which indicated that the soybean homogenate could not increase the amount of M. nipponense juveniles. Our results clearly showed that diet D significantly raised per unit yield of prawn seed comparing with no feeding and other diet group in extensive rearing systems and that the cost of producing prawn seed with diet D is low, which provide an important foundation for the expansion of oriental river prawn culture.  相似文献   

8.
Partial substitutions of fish meal by 5, 15, or 25 % of Gracilaria cornea or Ulva rigida in experimental diets were evaluated to study their effects on biodiversity of intestinal microbiota composition in gilthead seabream (Sparus aurata) juveniles. The diets were offered to duplicate groups of 15 juvenile fish (14.0 ± 0.5 g) for 70 days, and at the end of the experiment the intestinal microbiota from four specimens of each treatment was analysed by denaturing gel gradient electrophoresis. Results showed that the substitution of fish meal by algae meal induced important modifications in the intestinal microbiota community, as a big reduction of the biodiversity when the highest percentage (25 %) of U. rigida was included. On the contrary, an increase on the number of species was detected when a 15 % of algae was included. Various Lactobacillus delbrueckii subspecies were selectively stimulated when G. cornea was included in the feed, and other bacterial species, such as those included in the Vibrio genus, were reduced.  相似文献   

9.
The current study aimed to evaluate the possible effect of Origanum essential oil on innate immune parameters as well as the hematological profiles of Tilapia zillii following challenge with Vibrio anguillarum. Fifty-four of Tilapia zillii weighing 180?±?10.2 g were randomly distributed into three identical closed recirculating seawater systems. The study included three groups (G1, G2, and G3) repeated in triplicates. Fish of the first two groups were fed on a basal diet without herbs, whereas fish of the last group were fed on a basal diet supplemented with Origanum essential oil at concentration 1 g kg?1 for 15 days. Subsequently, fish of G2 and G3 subjected to a peritoneal inflammation by intraperitoneally injecting V. anguillarum (5.5?×?105 CFU mL?1), whereas fish of G1 injected with saline and served as control. Fish of all groups were then sampled at 4, 12, and 24 h post injection. No mortalities were observed in both basal and Origanum fed groups. However, some specimens of fish fed basal diet showed dorsal fin erosions, eroded mouth, and detached skin. Although the kinetics of RBCs, WBCs, Hb, and differential leukocyte values remained unchanged in fish fed different diets at the beginning of the trial, significant increases in those values were observed in fish fed Origanum essential oil at 12 and 24 h post injection. Similarly, an augmentation of plasma proteases, antiproteases, and lysozyme activities were recorded in fish fed Origanum essential oil at the same particular sampling points. A significant enhancement in plasma bactericidal capacity was only recorded in fish fed Origanum essential oil at 12 and 24 h post challenge compared to those fed basal diet. In conclusion, Origanum essential oil had a pronounced influence on the innate immunity and increased the fish resistance to V. anguillarum. These data gave insight into the potential use of Origanum in prophylactic strategies against threatening pathogens.  相似文献   

10.
The feeding experiment was conducted to evaluate the efficacy of locally available feed resources for Tra catfish (Pangasianodon hypophthalmus) cultured a series of 21 hapa net cages installed in the earthen pond during a 4-month period. The reference diet contained fish meal as the main crude protein (CP) source, whilst in the seven test diets 20–100 % of the fish meal CP was replaced with CP from local feed ingredients: groundnut cake (GNC), cassava leaf meal (CSLM), sweet potato leaf meal (SPLM), soybean meal (SBM), golden apple snail meal (GASM) and shrimp head meal. There were differences (p < 0.05) among diets in final body weight, total weight gain, daily weight gain, specific growth rate, viscera-somatic weight (VSI%), hepato-somatic index (HIS%) and intra-peritoneal fat (IPF%). The respective values for the shrimp head meal diet were numerically highest, followed in descending order by the reference, GASM, GNC, SPLM, CSLM and SBM diet. Food conversion ratio, fish survival rate, total feed intake, feed utilisation, fish fillet and kidney proportions did not differ among the reference and test diets (p > 0.05). However, the viscera-somatic, hepato-somatic, kidney and intra-peritoneal fat indices differed among treatments (p < 0.05). These data show that fish meal protein can be replaced with protein from locally available plant and animal feed ingredient resources in feed cultured in net cages in pond for Tra catfish fingerlings in effectively compromising growth performance, feed utilisation or carcass traits of fish.  相似文献   

11.
Administration of probiotic candidates in fish has generally been shown as a useful strategy to improve growth performance, survival, digestive enzyme activity, and gut microbiota. Unfortunately, the sero-immunological responses of different fish to different probiotic candidates are poorly understood. The present study assessed the effect of Pediococcus acidilactici as a probiotic on the biochemical and immunological parameters of beluga. Fish (248.32?±?10.21 g) were fed a control diet (without P. acidilactici( and three different doses of P. acidilactici-supplemented diets (107, 108, and 109 CFUg?1 diets) for 8 weeks. On week 8, blood and serum were sampled. Dose-dependent increase of immunological parameters (respiratory burst activity, lysozyme content, serum antibacterial activity, and total immunoglobulin) and biochemical parameters (total protein and albumin levels) was observed. However, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased in the juvenile beluga fed by 109 CFUg?1 P. acidilactici-supplemented diet compared to the other groups. Based on the results of this evaluation, it is reasonable to conclude that the inclusion of P. acidilactici as probiotic in diets for juvenile beluga improves the sero-immunological parameters of the fish and should be considered by farmers as a strategy to improve fish health.  相似文献   

12.
The yeast Saccharomyces cerevisiae is one of the commonest probiotics incorporated in aquafeeds. An 84-day feeding trial was conducted to evaluate the effects of varying dietary inclusions of S. cerevisiae, 0% (control), 3% (YF3), 5% (YF5), and 7% (YF7), on growth, stress tolerance, and disease resistance in juvenile (body mass ~?21 g) Nile tilapia (Oreochromis niloticus). Fish were randomly distributed in groups of 20 into 12 1-m3 hapas and fed isoenergetic (~?17 kJ g?1 gross energy) and isonitrogenous (~?300 g kg?1 crude protein) diets at 3% of their bulk weight daily. Specific growth rates were significantly higher for the yeast-fed fish (0.77–0.78% day?1) than for the control fish (0.60% day?1) and resulted in significantly higher mean final weights for the yeast-treated groups. Protein and lipid retention efficiencies were also significantly higher in the yeast-fed fish than in the control group. In subsequent stress challenge trials, the yeast-fed fish had greater tolerance to acute heat as well as hypoxia exposure than the control fish. Survival rates of the yeast-treated groups following sudden exposure to elevated water temperature (40 °C) ranged from 82.5 to 100% compared to 15% for the control. Mean survival rates following a 24-h hypoxia exposure were also generally significantly higher for the yeast-fed fish. The probiotic groups recorded a relative percent survival (RPS) of 75% after a 14-day Aeromonas hydrophila infection challenge. The results of this study indicate that S. cerevisiae as an additive in Nile tilapia diets has beneficial impacts on growth, stress tolerance, and disease resistance.  相似文献   

13.
The aim of the present study was to evaluate the effect of turmeric (Curcuma longa) as additive in the diet for Astyanax aff. bimaculatus. Fish (0.83 ± 0.04 g) were fed, for 60 days, with six diets containing 0.0, 20.0, 40.0, 60.0, 80.0, and 100.0 g turmeric kg?1 feed. There was an increasing linear effect of turmeric on the thickness of the muscular layer, and height and width of the folds of the intestine. In the liver, a quadratic effect was observed of turmeric on the percentage of hepatocyte cytoplasm and a decreasing linear effect on the percentage of sinusoid capillaries. A quadratic effect was also observed of turmeric on the liver glycogen. There was no effect of turmeric on the antioxidant activity in the liver, carcass composition or productive performance of the fish. Thus, we concluded that Curcuma longa has trophic effects on the epithelium and the muscular layer of the intestine of A. aff. bimaculatus. Additionally, low levels of Curcuma longa cause increased deposition of liver glycogen and high levels cause reduction.  相似文献   

14.
This study aimed to evaluate the effect of Lactococcus lactis K-C2 on the growth performance, microbial diversity, and release of free amino acids in the intestinal tract and the edible parts of young amberjack, Seriola dumerili. Fish were fed a diet with or without strain K-C2 (2?×?1010 cfu/g feed) for 25 days. The results indicated that the growth performance of fish in the treated group was significantly higher than those in the control group (p?<?0.05). The amount of five amino acids (aspartate, sarcosine, taurine, alanine, and arginine) in the gut content and 13 of 21 amino acids in the edible parts of fish in the treated group were significantly higher (p?<?0.05) than those in the control group. Sphingomonas, Propionibacterium, and Mycobacterium were observed in gut microflora of fish in both the control and treated groups. Staphylococcus and Kocuria were detected in one sample from the control and treated groups; Acinetobacter and Acidobacteria were found in one sample from the control group. L. lactis was only found in one sample in the treated group. In conclusion, the dietary administration of probiotic L. lactis stimulated growth, reduced feed consumption, and improved the nutritional value of cultured amberjack.  相似文献   

15.
The present study was carried out to evaluate the effect of dietary taurine (Tau) on performance, digestive enzymes, antioxidant activity, and resistance of common carp, Cyprinus carpio L., fry to salinity stress. Fish (0.97?±?0.033 g) were fed on different taurine levels of 0.0 (control), 5, 10, 15, or 20 g/kg diet up to satiation twice daily for 8 weeks. At the end of the feeding trial, fish were stressed by exposure to 10 ppt salinity for 3 days during which fish mortality was observed. Fish performance was significantly (P?<?0.05) improved by dietary taurine up to 15 g Tau/kg diet after which fish growth and feed intake were almost the same. Also, taurine supplementation significantly (P?<?0.05) elevated activities of intestinal amylase, lipase, and protease resulting in an improving in feed intake giving better performance. Furthermore, Tau-stimulated antioxidant activity of common carp was observed in a dose-related manner, where activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly (P?<?0.05) higher, but malondialdehyde (MDA) value was significantly (P?<?0.05) lower in Tau-fed fish groups than those fed the control diet. In salinity stress experiment, highest survival rate was observed at fish fed Tau-supplemented diets without significant (P?>?0.05) differences over fish fed the control diet. It appears that taurine could be used as a feed supplement to confer better growth and health of common carp fry with optimal level of 15 g/kg diet.  相似文献   

16.
The present study was conducted to demonstrate the dietary myo-inositol requirement and its effects on the growth, proximate composition and blood chemistry of Amur sturgeon (Acipenser schrenckii). Triplicate groups of 30 fish (initial weight 11.90?±?0.12 g) were fed different diets containing graded levels of myo-inositol (28.75, 127.83, 343.83, 565.81, 738.15 and 936.28 mg kg?1) until satiation for 56 days. The fish were weighed after a 24-h fast, and six fish were used for whole body composition analysis. Further, the liver and muscle were sampled from another six fish for lipid analysis. The blood and liver were sampled from the remaining six fish for haematology and fatty acid analysis. The weight gain of fish increased with myo-inositol content, from the 28.75- to 343.83-mg kg?1 myo-inositol treatment groups, and then stabilised. The liver lipid content and hepatosomatic index decreased significantly from 21.91 to 19.14% and from 3.20 to 2.76% with increased dietary myo-inositol supplementation, respectively. The whole body lipid content generally decreased from 6.33 to 5.55%. The content of liver-saturated fatty acids decreased significantly (28.13%) in the 936.28-mg kg?1 treatment group. The content of plasma non-esterified fatty acids increased with the increase in dietary myo-inositol supplementation from 0.77 to 1.17 mmol L?1, whereas the content of triglycerides significantly decreased from 4.62 to 3.28 mmol L?1. In conclusion, the optimum myo-inositol requirement was found to be 336.1 mg kg?1, based on weight gain in a two-slope quadratic broken-line model.  相似文献   

17.
In this study, Enterobacter cloacae bacterium was isolated from curd and its antibacterial potential against the pathogen Plesiomonas shigelloides was evaluated using the freshwater ornamental fish Kenyi cichlid (Maylandia lombardoi). Among the bacterial isolates, E. cloacae exhibited tolerance to acidic pH 2 and demonstrated the highest antibacterial activity against P. shigelloides in various in vitro assays. Dietary supplementation of E. cloacae with prebiotic supplement 2% mannan oligosaccharide improved the growth performance and reduced the toxic metabolites such as nitrite in culture tank water of Kenyi cichlid. In vivo application of E. cloacae with mannan oligosaccharide significantly elevated (p?<?0.05) white blood cell counts (88.47?±?2.15 103 mm?3) and respiratory burst activity (0.243?±?0.007) of Kenyi cichlid when challenged with P. shigelloides. Intestinal morphology of Kenyi cichlid fish treated with probiotic and prebiotic combinations showed improved intestinal architectures. The present findings confirm that the isolated bacterium E. cloacae is a potential probiotic and can be used effectively to prevent infection of P. shigelloides in freshwater ornamental fish culture.  相似文献   

18.
We isolated the rotifers Brachionus ibericus and Proales similis from the sediment of shrimp tanks and studied their individual demographic characters and competition between them at two food levels (0.25?×?106, 1.00?×?106 cells ml?1 of Nannochloropsis oculata at 25 °C) and salinities ranging from 10 to 30‰. Our hypothesis was that growth rates would be higher with increasing food levels and salinities. Observations were taken twice a day for life table studies and daily once for population growth experiments. Using survivorship and fecundity data, we derived various life history variables. Although the average life span (7.6?±?0.4 days) and gross reproductive rate (33.8?±?2.9 neonate female?1 day?1) of B. ibericus were higher than those of P. similis (average life span 5.4?±?0.6 days and gross reproductive rate 13.0?±?0.6 neonate female?1 day?1), the population growth experiments showed that P. similis had higher r values (0.32?±?0.005 day?1) than B. ibericus (0.23?±?0.002 day?1) at 1.0?×?106 cells ml?1 of N. oculata. The rotifer P. similis was more adversely affected due to the presence of B. ibericus than vice versa. The data are important for developing techniques for a large-scale culture of these rotifers as food in aquaculture.  相似文献   

19.
Sciaenops ocellatus has a long history in aquaculture and many difficulties associated with its commercial culture have been addressed and successfully resolved; nevertheless, further research in lipid nutrition could address more comprehensive questions on the way these nutrients are utilized. The purpose of this study was to evaluate S. ocellatus growth and lipase gene expression in response to increasing dietary lipid supplementation. Four experimental diets were formulated to provide 3, 10, 16, or 23% lipid using menhaden fish oil. Twenty juveniles (mean initial weight 2.3?±?0.1 g) were stocked per aquaria in a recirculating system; each diet was assigned to three aquaria and fed to fish for 6 weeks. At the end of the study, fish fed 3% of dietary lipid were significantly (P?<?0.0001) smaller and showed significantly lower feed efficiency, condition factor, hepatosomatic index, and intraperitoneal fat than fish fed the other diets, but no differences were observed among fish fed 10, 16, or 23% lipid. A straight broken-line regression model for thermal growth coefficient provided an estimated value of 9.4% of dietary lipid as the optimal inclusion level. The bile salt-dependent lipase (BSDL) of red drum was 80.3 kDa. Relative gene expression of BSDL was significantly higher (P?=?0.0007) in fish fed 10% lipid, with no differences among the other dietary treatments. Results provided could help monitor the metabolic status of farmed fish and contribute to optimize diet formulations based on maximum gene expression of BSDL for supplementation of dietary lipid.  相似文献   

20.
This study was designed to assess the potential effects of Astragalus membranaceus (AM) on the growth performance and antioxidative stress response in bluegill sunfish (Lepomis macrochirus) exposed to challenging cold water temperature conditions. In this regard, fish with an average weight of 43 ± 1 g were divided into four groups and fed daily with an AM-free diet (control), and 1.5, 3, and 4.5 % (w/w) AM-incorporated diets for an 8-week period. Oxidative stress response, biochemical, and growth parameters were measured, and subgroups of fish were exposed to the outside challenging cold pond water temperature (1.6–9.9 °C) with an average of 7.0 ± 0.1 °C beyond the optimal temperature. The results showed that incorporating AM in the diet significantly improved growth performance parameters (body mass gain, specific growth rate, length, condition factor, and feed conversion ratio) and biochemicals (aspartate aminotransferase and alanine transaminase activities, and glucose and cortisol concentrations). In addition, markedly up-regulated superoxide dismutase, glutathione peroxidase, and catalase activities were observed in AM-treated fish groups over the control. Conclusively, feeding AM diets significantly increased (P < 0.05) growth performance and antioxidative stress profiles throughout the entire experiment, and this increase was much more pronounced at 8 weeks after the water temperature began to rise, which can be related to the nature of Bluegill fish as it is known to be a warm water fish. These findings are considered to be of great importance for sustainable aquaculture.  相似文献   

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